The present invention relates generally to a fastener used to secure a vehicle component to the frame of the vehicle.
In the manufacture of vehicles such as automobiles, it is a common practice to pre-assemble certain portions of the vehicle remotely from the main assembly line. These pre-assembled portions are then brought to the main assembly line and assembled with the remainder of the vehicle in a process that is generally faster than assembling each component part at the main assembly line. This process is used for both large assemblies, such as motors and the like, and for smaller components and accessories such as grab handles, door handles, or hang hooks.
A typical means of securing an accessory to the interior of an automobile is to utilize a common, threaded fastener, which passes through the accessory and into the frame or substrate of the vehicle. Unfortunately, the structures that enable the use of threaded fasteners tend to be rather complicated, requiring numerous parts and steps in their assembly. Accordingly, there is a need for a simplified structure for attaching vehicle accessories to the substrate of the vehicle.
The shortcomings of the prior art are satisfied by a grommet assembly that is adapted for securing an accessory to the substrate, i.e. frame, of a vehicle. The grommet assembly comprises a lower grommet having a retaining structure adapted for securing the grommet assembly to the substrate of the vehicle, and an upper grommet having a slot that is constructed and arranged to receive and retain an end of the accessory therein. The upper and lower grommets have bores that are substantially aligned when the upper and lower grommets are registered with one another. A fastener passed through the bore in the upper grommet simultaneously passes through a hole or bore formed in the end of the accessory and into the bore formed in the lower grommet. Once this fastener is driven home, the upper and lower grommets are secured to one another, and the end of the accessory will be retained in the grommet assembly. A cap for covering all or a portion of the upper and lower grommets may be secured to the upper grommet, though the cap may also be adapted to be coupled to the lower grommet. Depending on the application, the cap of the grommet assembly may need to be assembled with the accessory before the end of the accessory is inserted into the upper grommet. Once the upper and lower grommets and cap have been assembled with one another so as to securely retain the end of the accessory therein, the grommet assembly is referred to as a part-in-assembly (PIA). This part-in-assembly may then be transported to an assembly line for assembly with a vehicle.
The retaining structure of the lower grommet secures the grommet assembly to the substrate of a vehicle. To that end, the shaft of the retaining structure typically has a snap fit mechanism or the like formed thereon. Suitable snap fit mechanisms may include flexible tabs, detents, a plurality of frustoconical vanes, and laterally extending wings. Where suitable, a friction or interference fit between the retaining structure and the bore formed through the substrate of the vehicle may suffice. Note that in a preferred embodiment of the present invention, the bore formed into the lower grommet will also extend into the shaft of the retaining structure.
Where rotation of the grommet assembly would be detrimental, a lower grommet may be provided with an additional structure that is referred to as an anti-rotation stem. This stem is a simple projection that extends downwardly from the undersurface of the lower grommet similar to the retaining structure. The stem is inserted into a bore simultaneous with the insertion of the retaining structure into a respective bore formed through the substrate of the vehicle.
The structure of the present invention enables a relatively simple method for installing an accessory in the substrate of a vehicle. The method of installing an accessory in a vehicle begins with the step of inserting an end of an accessory into a slot that is formed in the upper grommet, taking care to insure that a bore formed through the end of the accessory is in registration with a bore that passes through the upper grommet so as to intersect the slot of the upper grommet. Once this is complete, the lower surface of the upper grommet is registered with an upper surface of the lower grommet such that a bore that is formed in the lower grommet is in substantial alignment with the bore formed through the upper grommet. Note that the lower grommet has extending downwardly from an undersurface thereof a retaining structure that is preferably also aligned with the bore formed through the lower grommet. In a preferred embodiment, the bore formed into the lower grommet extends at least partially into this retaining structure.
A fastener is next driven through the bores formed through the upper grommet, the end of the accessory, and the lower grommet so as to simultaneously secure the upper grommet to the lower grommet while retaining the end of the accessory within the slot in the upper grommet. Finally, the retaining structure of the lower grommet is addressed to a bore formed through the substrate of a vehicle and inserted therein, thereby securing the accessory to the substrate of the vehicle.
Note that in some circumstances, a cap will be assembled with the upper grommet prior to inserting the retaining structure of the lower grommet into the bore formed in the substrate of the vehicle. In addition, where rotation of the accessory is unwanted, an anti-rotation stem may be provided on a lower surface of the lower grommet and inserted into a bore formed in the substrate simultaneous with the insertion of the retaining structure of the lower grommet into a separate bore formed through the substrate.
These and other objects, aspects, features and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators.